visual receptors

• Photoreceptors detect light
• photoreceptors are considered transducers as they convert light energy to electrical energy.
• When light enters the eye and hits the retina it passes through the layers of optic nerve and neurons and is absorbed by photosynthetic pigments in photoreceptors. the light causes a chemical change and alters membrane permeability to sodium ions. this generates potential and if threshold is reached then an impulse is sent along.